Targeted isolation of sesquiterpene lactone dimers from Aucklandia lappa guided by LC-HRMS/MS-based molecular networking

An LC-HRMS/MS-based molecular networking strategy was applied to investigate the potential sesquiterpene dimers of Aucklandia lappa, leading to the isolation of three undescribed guaiane-guaiane dimers and one guaiane-eudesmane dimer together with six known sesquiterpenes. The structures were determined by analyzing their 1D, 2D NMR, and HRESIMS data as well as ECD calculations. The biogenetic pathway of the sesquiterpene dimers was postulated to involve the Diels-Alder cycloaddition as the key step. All compounds exhibited their inhibitory effects on LPS-induced nitric oxide production in RAW 264.7 macrophages with IC₅₀ values ranging from 0.3 to 25.1 μM.

First report of Meloidogyne hapla infecting Yunmuxiang (Aucklandia lappa) in China

Yunmuxiang (Aucklandia lappa) is a tall, perennial herbaceous plant in the compositae family, occurring mainly in Asia and Europe. Yunmuxiang originated in India and was introduced into China in approximately 1940. Since then it has been widely cultivated in the southwest region of China for medicinal uses; it is included in the Chinese Pharmacopoeia. Yunmuxiang is used primarily as a sedative, including for anesthesia (Ting et al. 2012). Severely stunted and withered Yunmuxiang plants with rotted and galled roots were observed in a field in near the city of Lijiang (N 99°46'; E 27°18') in October 2019. These symptoms were typical of infection by root-knot nematodes.The second-stage juveniles (J2) were collected from the soil in the root zone, and adult females were dissected from roots. Population densities of J2 ranged from 325 to 645 per 100 cm3. Morphological analysis and species-specific PCR were performed on the second stage (J2) and females. Morphological characteristics are as follows: for J2 (n=20) , body length = 360.5 ± 23.4 µm, tail length = 47.2 ± 6.1 µm, and stylet length = 10.4 ± 1.9 µm, distance from dorsal esophageal gland opening to the stylet knot (DGO) = 3.96 ± 0.42 μm; females (n = 20) were pear-shaped, body length = 565.23 ± 86.68 μm, maximum body width = 407.24 ± 60.21 μm, stylet length = 9.93 ± 0.88 μm, DGO = 4.76 ± 0.32 μm, stylet median bulb width (MBW) = 29.67 ± 3.61 μm, perineum morphology is low and low dorsal arch round, with a typical inferior protrusion near the anus. These morphological characteristics are consistent with Meloidogyne hapla as described by Hunt and Handoo (2009). To confirm species identification, DNA was extracted from females (Blok, et al. 1997) and ITS region was amplified using the primers 18S/26S (Vrain et al. 1992). Furthermore, species-specific SCAR primers JMV1/JMV hapla were used as described by Adam et al. (2007). PCR produced 768 bp and 419 bp sequences. Fragments were sequenced (MW512922and MW228371, respectively) and compared with available sequences on NCBI. Sequences were 99.48% identical to the MT249016, KJ572385, and 100% identical to the GQ395574, GQ395569 M. hapla sequences, respectively. Morphological and molecular characterization supports the identification of the isolate found on Aucklandia lappa as M. hapla. Yunmuxiang seed were planted in 20 cm diameter, 10 cm deep plastic pots containing 1000 cm3 sterilized soil. Seedlings were thinned to one per pot. At the 2-3 leaf stage 10 pots were infested with 1500 M. hapla J2 per seedling, using a sterilized micropipette. Plants were maintained at 20-25°C in a greenhouse. Control plants received sterile water, and the pathogenicity test was repeated three times. After 30 days, plants were removed from pots and soil gently removed from the roots. A large number of galls (95.6 ± 2.5) and egg masses (33.5 ± 0.5) were found on each root system. Yunmuxiang was considered a good host for M. hapla in Lijiang. M. hapla is a major plant parasitic nematode with a wide geographic distribution and range of host plants and causes severe yield losses (Azevedo de Oliveira et al. 2018). Through investigation, this is the first report worldwide of M. hapla infecting Aucklandia lappa.

Aucklandia lappa Causes Membrane Permeation of Candida albicans

Candida albicans is a major fungal pathogen in humans. In our previous study, we reported that an ethanol extract from Aucklandia lappa weakens C. albicans cell wall by inhibiting synthesis or assembly of both (1,3)-β-D-glucan polymers and chitin. In the current study, we found that the extract is involved in permeabilization of C. albicans cell membranes. While uptake of ethidium bromide (EtBr) was 3.0% in control cells, it increased to 7.4% for 30 min in the presence of the A. lappa ethanol extract at its minimal inhibitory concentration (MIC), 0.78 mg/ml, compared to uptake by heat-killed cells. Besides, leakage of DNA and proteins was observed in A. lappa-treated C. albicans cells. The increased uptake of EtBr and leakage of cellular materials suggest that A. lappa ethanol extract induced functional changes in C. albicans cell membranes. Incorporation of diphenylhexatriene (DPH) into membranes in the A. lappa-treated C. albicans cells at its MIC decreased to 84.8%, after 60 min of incubation, compared with that of the controls, indicate that there was a change in membrane dynamics. Moreover, the anticandidal effect of the A. lappa ethanol extract was enhanced at a growth temperature of 40°C compared to that at 35°C. The above data suggest that the antifungal activity of the A. lappa ethanol extract against C. albicans is associated with synergistic action of membrane permeabilization due to changes in membrane dynamics and cell wall damage caused by reduced formation of (1,3)-β-D-glucan and chitin.

Analgesic and Anti-Inflammatory Effects of Aucklandia lappa Root Extracts on Acetic Acid-Induced Writhing in Mice and Monosodium Iodoacetate-Induced Osteoarthritis in Rats

Osteoarthritis (OA) is an age-related joint disease and one of the most common degenerative bone diseases among elderly people. The currently used therapeutic strategies relying on nonsteroidal anti-inflammatory drugs (NSAIDs) and steroids for OA are often associated with gastrointestinal, cardiovascular, and kidney disorders, despite being proven effective. Aucklandia lappa is a well-known traditional medicine. The root of A. lappa root has several bioactive compounds and has been in use as a natural remedy for bone diseases and other health conditions. We evaluated the A. lappa root extracts on OA progression as a natural therapeutic agent. A. lappa substantially reduced writhing numbers in mice induced with acetic acid. Monosodium iodoacetate (MIA) was injected into the rats through their knee joints of rats to induce experimental OA, which shows similar pathological characteristics to OA in human. A. lappa substantially reduced the MIA-induced weight-bearing of hind limb and reversed the cartilage erosion in MIA rats. IL-1β, a representative inflammatory mediator in OA, was also markedly decreased by A. lappa in the serum of MIA rats. In vitro, A. lappa lowered the secretion of NO and suppressed the IL-1β, COX-2, IL-6, and iNOS production in RAW264.7 macrophages activated with LPS. Based on its analgesic and anti-inflammatory effects, A. lappa could be a potential remedial agent against OA.

Aucklandia lappa Causes Cell Wall Damage in Candida albicans by Reducing Chitin and (1,3)-β-D-Glucan

The fungal cell wall is a major target of antifungals. In this study, we report the antifungal activity of an ethanol extract from Aucklandia lappa against Candida albicans. We found that the extract caused cell wall injury by decreasing chitin synthesis or assembly and (1,3)-β-D-glucan synthesis. A sorbitol protection assay demonstrated that the minimum inhibitory concentration (MIC) of the A. lappa extract against C. albicans cells increased eight-fold from 0.78 to 6.24 mg/ml in 72 h. Cell aggregates, which indicate damage to the cell wall or membrane, were commonly observed in the A. lappatreated C. albicans cells through microscopic analysis. In addition, the relative fluorescence intensities of the C. albicans cells incubated with the A. lappa extract for 3, 5, and 6 h were 92.1, 84.6, and 79.8%, respectively, compared to the controls, estimated by Calcofluor White binding assay. This result indicates that chitin content was reduced by the A. lappa treatment. Furthermore, synthesis of (1,3)-β-D-glucan polymers was inhibited to 84.3, 79.7, and 70.2% of that of the control treatment following incubation of C. albicans microsomes with the A. lappa extract at a final concentration equal to its MIC, 2× MIC, and 4× MIC, respectively. These findings suggest that the A. lappa ethanol extract may aid the development of a new antifungal to successfully control Candida-associated disease.

Effect of Dehydrocostus Lactone Isolated from the Roots of Aucklandia lappa on the Apoptosis of Endometriotic Cells and the Alternative Activation of Endometriosis-Associated Macrophages

The roots of Aucklandia lappa have been used in traditional medicine in Asia to treat inflammation and diseases associated with pain, including endometriosis. The aim of this study was to investigate the anti-endometriotic effect of dehydrocostus lactone, an active compound in A. lappa roots, using human endometriotic cells and macrophages stimulated by these cells. Dehydrocostus lactone induced apoptotic cell death in 12Z human endometriotic cells. Dehydrocostus lactone stimulated the activation of caspase-3, -8, and -9, while caspase inhibitors significantly reversed the dehydrocostus lactone-induced cell death in 12Z cells. In addition, dehydrocostus lactone decreased the production of PGE₂ and neurotrophins (BDNF, NGF, NT3, and NT4/5), which are regarded as endometriosis-associated pain factors in human endometriotic cells. Moreover, dehydrocostus lactone inhibited the expression of M2 markers (CD206, and Trem-2), IL-10, VEGF, and MMP-2/-9 in endometriosis-associated macrophages (EAMs). Furthermore, dehydrocostus lactone inhibited the Akt and NFκB pathways in both endometriotic cells and EAMs. Taken together, our findings suggest that dehydrocostus lactone, an active compound of A, lappa, has anti-endometriotic activities via induction of apoptosis and downregulation of pain factors in endometriotic cells and inhibition of the alternative activation of EAMs.

Preparation of Herbal Formulation for Inflammatory Bowel Disease Based on In Vitro Screening and In Vivo Evaluation in a Mouse Model of Experimental Colitis

Many medicinal plants have been used traditionally in East Asia for the treatment of gastrointestinal disease and inflammation. The aim of this study was to evaluate the anti-inflammatory activity of 350 extracts (175 water extracts and 175 ethanol extracts) from 71 single plants, 97 mixtures of two plants, and seven formulations based on traditional medicine, to find herbal formulations to treat inflammatory bowel disease (IBD). In the in vitro screening, nitric oxide (NO), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 levels were determined in LPS-treated RAW264.7 cells and the TNF-α induced monocyte-epithelial cell adhesion assay was used for the evaluation of the anti-inflammatory activity of the compounds. Dextran sulfate sodium (DSS)-induced colitis model and 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis model were used to evaluate the therapeutic effect against IBD of the samples selected from the in vitro screening. KM1608, composed of Zingiber officinale, Terminalia chebula and Aucklandia lappa, was prepared based on the screening experiments. The oral administration of KM1608 significantly attenuated the severity of colitis symptoms, such as weight loss, diarrhea, and rectal bleeding, in TNBS-induced colitis. In addition, inflammatory mediators, such as myeloperoxidase, TNF-α, and IL-6 levels decreased in the lysate of colon tissues treated with KM1608. Collectively, KM1608 ameliorated colitis through the regulation of inflammatory responses within the colon, which indicated that KM1608 had potential for the treatment of IBD.

Molecular identification and cytotoxicity study of herbal medicinal materials that are confused by Aristolochia herbs

Herbal materials derived from Aristolochia species contain carcinogenic aristolochic acids (AAs) and have been used as traditional Chinese medicines (TCMs) or adulterants of other TCMs. The purpose of this study is to identify the TCMs Stephaniae Tetrandrae Radix, Akebiae Caulis, Aucklandia Radix and Aristolochiae Fructus by sequencing the matK, rbcL, trnH-psbA and trnL-trnF DNA regions. The cytotoxicities of AAs and these TCMs were also studied in COS-7 and HEK-293 cells. Diagnostic polymorphic sites were identified in all the four DNA loci for the differentiation of genuine herbs from their adulterants/substitute. The 48 h IC50 of AAI were 78 μM (COS-7) and 70 μM (HEK-293) while the IC50 of AAII were higher than 100 μM in both cell lines. Except Aucklandia Radix, cytotoxicity study also showed that AA-containing herbs were more toxic than their corresponding genuine herbs and substitute.